/*******************************************************

* Copyright (c) 2015, ArrayFire

* All rights reserved.

*

* This file is distributed under 3-clause BSD license.

* The complete license agreement can be obtained at:

* http://arrayfire.com/licenses/BSD-3-Clause

********************************************************/

#include <arrayfire.h>

#include <cstdio>

#include <cstdlib>

using namespace af;

static void fast_demo(bool console) {

// Load image

array img_color;

if (console)

img_color = loadImage(ASSETS_DIR "/examples/images/square.png", true);

else

img_color = loadImage(ASSETS_DIR "/examples/images/man.jpg", true);

// Convert the image from RGB to gray-scale

array img = colorSpace(img_color, AF_GRAY, AF_RGB);

// For visualization in ArrayFire, color images must be in the [0.0f-1.0f]

// interval

img_color /= 255.f;

features feat = fast(img, 20.0f, 9, true, 0.05);

float* h_x = feat.getX().host<float>();

float* h_y = feat.getY().host<float>();

// Draw draw_len x draw_len crosshairs where the corners are

const int draw_len = 3;

for (size_t f = 0; f < feat.getNumFeatures(); f++) {

int x = h_x[f];

int y = h_y[f];

img_color(y, seq(x - draw_len, x + draw_len), 0) = 0.f;

img_color(y, seq(x - draw_len, x + draw_len), 1) = 1.f;

img_color(y, seq(x - draw_len, x + draw_len), 2) = 0.f;

// Draw vertical line of (draw_len * 2 + 1) pixels centered on the

// corner Set only the first channel to 1 (green lines)

img_color(seq(y - draw_len, y + draw_len), x, 0) = 0.f;

img_color(seq(y - draw_len, y + draw_len), x, 1) = 1.f;

img_color(seq(y - draw_len, y + draw_len), x, 2) = 0.f;

}

freeHost(h_x);

freeHost(h_y);

printf("Features found: %zu\n", feat.getNumFeatures());

if (!console) {

af::Window wnd("FAST Feature Detector");

// Previews color image with green crosshairs

while (!wnd.close()) wnd.image(img_color);

} else {

af_print(feat.getX());

af_print(feat.getY());

}

}

int main(int argc, char** argv) {

int device = argc > 1 ? atoi(argv[1]) : 0;

bool console = argc > 2 ? argv[2][0] == '-' : false;

try {

af::setDevice(device);

af::info();

printf("** ArrayFire FAST Feature Detector Demo **\n\n");

fast_demo(console);

} catch (af::exception& ae) {

fprintf(stderr, "%s\n", ae.what());

throw;

}

return 0;

}